Scientists set for creation of human embryo with two mothers

Published on 09/09/2005 00:09

SCIENTISTS in Britain have been given permission to create a human embryo that will have genetic material from two mothers.

Researchers at Newcastle University plan to transfer the nucleus of a human embryo made by a man and a woman into an unfertilised egg from another woman. It is hoped the groundbreaking experiment will help prevent mothers from passing on certain genetic diseases to their unborn babies. Such genetic conditions are known as mitochondrial diseases.

The team's application was initially rejected by the Human Fertilisation and Embryology Authority (HFEA) but was granted following an appeal.

However, opponents believe it is another step on the road to so-called "Frankenstein babies". Josephine Quintavalle, from the pro-life group Comment on Reproductive Ethics, said: "This shows once again that the HFEA does not have any regard for public consultation and the views of the public."

Mitochondria are small complex structures which exist in every cell of the body, except red blood cells. A unique feature is that they have their own DNA, which is inherited from the mother only. If this DNA is faulty, mitochondrial diseases occur. At present, no treatment for mitochondrial diseases exists, but the new technique means that women carrying the faulty DNA can now have it replaced by genetic material from a healthy woman.

Studies in mice show it is possible to prevent the transmission of mitochondrial disease by moving the nucleus from an egg containing bad mitochondria to another egg, which contains only good mitochondria.

Doug Turnbull, Professor of Neurology at Newcastle University, and Dr Mary Herbert, scientific director of the Newcastle Fertility Centre, now plan to do the same in humans.

The goal of the research, funded by the Muscular Dystrophy Campaign, is to check that transplanting the nucleus works and is safe. The resulting egg would never be allowed to develop into a baby.

But even if it did, the offspring would still resemble the mother and father because the mitochondrial DNA does not dictate things like hair colour.

About one in 5,000 children and adults are at risk of developing a mitochondrial disease, such as muscular dystrophy and Leigh's syndrome, a progressive neuro-degenerative disorder.

In its ruling, the HFEA said it was satisfied the research activities were "necessary and desirable" under the criteria in the HFE Act and use of embryos was "necessary for the research".

Last year, Britain became the first western nation to embrace human cloning technology when the HFEA allowed scientists at Newcastle University to clone human embryos for medical research. The new licence will add to the UK's growing reputation for expertise in the field of cloning research.

Dr Virginia Bolton, consultant clinical embryologist at Guy's Hospital in London, said: "This is yet another example of the value of human embryo research to establish the safety of a technique before it is introduced into clinical practice. This means that, rather than using the adult couple and prospective baby as experimental material, we can use a human embryo donated to research to provide the vital information."

ENERGY FAILURE

MITOCHONDRIAL conditions include more than 40 identified diseases that have different genetic features.

As mitochondria are the "powerhouses" of cells, producing most of the energy required to grow and live, the common factor of babies born with the diseases is that they are unable to completely burn food and oxygen in order to generate energy.

Organs in the body which require high energy to work properly, such as the brain, heart and kidney, are particularly dependent on well-functioning mitochondria.

Depending on how severe the mitochondrial disorder is, the illness can range in severity from mild to fatal.

Symptoms can include poor growth, loss of muscle co-ordination, muscle weakness, visual or hearing problems, learning disabilities, heart, liver or kidney disease, gastrointestinal and respiratory disorders, diabetes and dementia.